The system of care and support for the 1.5 million people who have a learning disability is breaking down because of spending cuts and an "alarming" shortage of accommodation, according to consultants commissioned by the Department of Health.

There is a "pressing need" for the government to intervene to set a clear strategy and to prevent many care providers going out of business, the Laing & Buisson consultancy says in a report.

It comes ahead of a BBC Panorama special on Tuesday, which will include secret filming of what is described as "physical assaults, systematic brutality and torture" of men and women with a learning disability by staff at a private unit, believed to be near Bristol. The programme is certain to spark a debate about the wider treatment of people with a learning disability, whose numbers are growing by up to 5% a year and who can require care and support costing a typical £1,500 a week.

Laing & Buisson was commissioned by the department to report on the relative costs of different models of care and support. That analysis remains unpublished by the department, but the consultancy has released a separate report based on its findings "as a springboard for further discussions".

The study says local authorities, which are responsible in England for arranging care and support, are cutting both hours they pay for, and rates they offer, and "there is a real danger that support is already, in some cases, and will increasingly be, insufficient to meet the fundamental rights and support requirements of people with learning disabilities and will jeopardise their wellbeing".

Squeezing the rates paid to companies and charities, which provide almost all paid-for care and support, may mean a reduction in the quality of service or even a shortage of supply.

There is already a severe shortage of suitable housing for people with a learning disability, the report says. Doubts about viability of the existing system are undermining the prospects of investment by providers and support for them from the banks.

Hopes for a change in funding rest on a report due in July from a government commission led by economist Andrew Dilnot, who has been tasked with finding sustainable solutions to the challenges of funding the care of people with disabilities.

William Laing, chief executive of Laing & Buisson, said: "Unless these issues are better recognised and more holistically addressed, for instance through extra funding by the commission, there is an increasing likelihood that many providers will go out of business."

The department said that the Laing & Buisson report would be published "in due course".

Undercover care – The Abuse Exposed: Panorama on BBC1 at 9pm on 31 May